1. Technical Field
The present invention relates to caller detection and more particularly to a system and method for determining spam and unsolicited calls.
2. Description of the Related Art
Anonymity of Internet Protocol (IP) users is a key problem in providing services over the Internet. This affects all services including Voice-over-IP (VoIP) based services. While telephone fraud has always been a problem, the Internet has made this problem more serious because automation of fraud has become much easier. Therefore, it is important for both service providers and users to stop automated attacks that are delivered over IP.
Session Initiation Protocol or SIP, is a signaling protocol for Internet conferencing, telephony, events notification and instant messaging. In SIP and VoIP networks, unsolicited messages and calls can be automatically generated and delivered to phones in a cheaper and faster manner than in telephone networks.
Consider two types of spam: (1) Call Spam. Call Spam is where the caller wishes to successfully initiate a dialog and have a media session. For example, unsolicited calls that are automatically initiated and carried out by software using ‘pre-recorded’ streams similar to telemarketing calls today. (2) Call initiation spam. Call initiation span is where the caller does not wish to successfully initiate a dialog and have a media session. For example, unsolicited INVITE spam with spoofed SIP URIs or IP addresses.
While telephone network span (telemarketing) may be solved using legislation, IP networks cross international borders and spammers may not be in a jurisdiction in which certain laws apply. Email spam issues may be solved using spam filters that passively analyze headers and content contained in individual email messages. This is not guaranteed to be effective because headers can be forged or spoofed. Further, content analysis is not guaranteed to be effective for VoIP span because content cannot be analyzed until a call is already established and the content has already being transmitted.
Third party infrastructure services such as reputation systems and consent-based communications can be used to verify callers. However, third party infrastructure services require both caller and callee to participate in such systems.